TECHNICAL DATASHEET CARAPACE EMP110 HD High Definition PHOTOIMAGEABLE SOLDERMASK

Transcription

1 PRODUCT DESCRIPTION TECHNICAL DATASHEET CARAPACE EMP110 HD High Definition PHOTOIMAGEABLE SOLDERMASK Carapace EMP110 has been used in the high volume production of PCBs since Carapace EMP110 HD is the latest development of the range, formulated to exceed the increasing demands of PCB processes, combined with a large process window. Fine solder dam resolution (50µm, (2 mil). 50 micron solder-dams (exposed using Olec ATH30) Fast processing times allowing high throughput and productivity. Optimised rheological and coating properties for each method of application. Low ionic contamination. Solderball elimination. High moisture and insulation resistance High resistance to low solids fluxes. Excellent adhesion to flexible substrates. Low odour. TGIC-Free version suitable for all final finish requirements Halogen-free Reach and RoHS compliant Carapace EMP110 is a contact exposure, aqueous developing, liquid photoimageable soldermask, using twocomponent epoxy technology to give high levels of chemical resistance over copper, copper oxide or gold plated circuits. Due to their resolution capability, high dielectric strength and physical resistance properties Carapace EMP110 soldermasks are used as solder resists and insulation coverings on all types of printed circuits, particularly highreliability, double-sided and multilayer, fine line, surface mount boards. Page 1 of 10

2 CARAPACE EMP110 PRODUCT RANGE PASTES: All Carapace pastes are coded as EMP110 followed by numbers and letters. The number and letters denote the colour, finish and application method. Carapace EMP110 HD is available as standard in the following: Screen-print: EMP110/5158 TG HD (Transparent Gloss) EMP110/5410 TM HD (Transparent Matt) Air-spray: EMP110/5393EM TG HD AS (Transparent Gloss) EMP110/5396EM TM HD AS (Transparent Matt) HARDENERS: 1) EMP110 PtB - The following hardener is grouped into the EMP110 PtB class: EMP110 Pt B (H-4090) EMP110 Pt B (H-4090 G) EMP110 Pt B (H-4090 DG) EMP110 Pt B (H-4090 LG) EMP110 Pt B (H-4090 N) EMP110 Pt B (H-4090 B) EMP110 Pt B (H-4090 R) Transparent Green Dark Green Light Green Black Blue Red Page 2 of 10

3 Board surface preparation: Mechanical pre-cleaning: Brush 320 to 400 grit silicon carbide brushes with a recommended footprint on the copper of 10-15mm. ( inches). Brushes should be regularly checked and dressed to ensure optimum preclean is retained. Pumice Slurry Scrub Pumice concentration between 18-22% (v/v) is recommended (3F or 4F virgin grade). Slurry should be changed between panels Aluminium Oxide Slurry Scrub Aluminium oxide concentration between 18-22% (v/v) is recommended (400 grit). Slurry should be changed between at least 20,000-30,000 panels Aluminium Oxide Jet Slurry Spray is known to give lower surface roughness compared to other pre-clean methods. Where no other alternative method is available then the following conditions are suggested: Aluminium oxide concentration between 18-22% (v/v) is recommended (220 grit virgin grade). Jet spray pressure PSI ensuring the jet nozzle patterns fully overlap Slurry should be changed between at least 10,000-20,000 panels Panels must be fully rinsed such that any slurry particles are completely removed. Failure to remove particles can result in poor cosmetics and adhesion loss. If panels are heavily oxidised and tarnished then a micro-etch prior to mechanical pre-cleaning is strongly recommended. Panels must be thoroughly rinsed prior to mechanical cleaning stage. Recommended Surface roughness figures are Ra μm. Chemical pre-cleaning: High Roughness, Deep-Etching Clean Due to the excellent mechanical bond achieved between the copper surface and soldermask, proprietary deepetch chemistries are the preferred method of pre-clean. For a list of recommended and approved chemistries, please contact your Electra representative. Microetch Clean Simple microtech solutions such as sodium persulphate are not recommended as the sole method of preclean. In all cases panels must be thoroughly rinsed and dried such that no tarnish is present and no water moisture remains in the holes or between closely spaced tracks. It is recommended that all freshly cleaned panels are coated within 2-4 hours. The actual maximum time will vary depending upon ambient temperature and humidity. Panels left longer than 4 hours should be re-cleaned prior to coating. Page 3 of 10

4 Mixing: Carapace EMP110 HD is supplied in pre-weighed packages of paste + hardener. The original supplied mix ratio must be used if mixing smaller amounts than the standard pack-size. Stir well to ensure complete mixing. Incomplete mixing can cause poor developing, stickiness during exposure and impaired final properties. Viscosity reduction: SP formulations: SP versions of EMP110 are supplied screen ready. If viscosity adjustment is required prior to, or during printing, then this may be achieved using Electrareducer ER1. No more than 5% reducer should be added or deterioration of the printing and drying properties may occur, resulting in thin deposits on track edges and/or prolonged drying times. AS formulations: It is advisable to use a slow speed mechanical mixer when mixing in solvent. Care should be taken to avoid incorporating air into the resist during mixing. Resist should be allowed to stand for 2 hours after mixing to allow air to escape. Excessive air in resist can cause microbubbles/voids in the finished film and/or poor curtain stability when curtain-coating EMP110 HD AS soldermasks using EMP110 Pt B H-4090 should be reduced with Electrareducer ER6. Where ER6 is not available, an equivalent from an approved source may be used. The use of non-approved solvents is not recommended as they can cause contamination and other processing problems. Addition level required will depend on spray system used. Please contact Electra Technical Support Department for recommendation addition levels Due to the fast viscosity readings using a Zahn 3 cup, air inclusion can give erratic readings. It is therefore recommended to use the Ford Nº4 or a cup giving similar values (e.g. Frikmar Nº4). Process settings: Flat-bed screen printing: Mesh count: Squeegee: 36-54T/cm ( mesh) polyester Shore. 20μm dry thickness should be aimed for; this is typically achieved using a 43T/cm (110 mesh) The board outline image may be made on the screen using conventional stencil material or masking tape and screen filler. To prevent a build up of ink on the reverse of the screen that may block holes, it is advisable to shift alternate boards along the x- or y-axis before printing. Alternatively, a rudimentary stencil, such as an expanded drill mask, can be used on the screen to prevent ink going into the holes. Do not utilise the vacuum bed, as this will suck an exaggerated amount of ink into the holes. Page 4 of 10

5 Double-side screen printing (Circuit Automation DP machines) : Mesh count: Squeegee: 32-38T/cm (83 98 mesh) polyester Shore. Typically a flood-print-print cycle is recommended. Wherever possible the ISO-print feature is recommended to reduce ink deposit into larger holes. Vacuum chamber de-gassing prior to tack-drying is proven to reduce bubbling between tracks and reduce viahole popping due to solvent entrapment. Air Spray: Exact spray parameters will depend on track height and circuit layout. These parameters will also depend on equipment manufacturer, please contact Electra Technical Support Department for specific recommendations. Below are general recommendations and guidelines: Wet-thickness: 60 to 100µm (1.2 to 4 mils) Tank pressure and coating speed are set to give desired wet thickness. Atomising pressure should be set to give minimal mottling. Shaping air is to be adjusted to give an even spray pattern. Lower atomising pressures and higher coating speeds will lead to increased mottling. Tack-dry: The aim of the tack-drying stage is to solely remove the solvents. It is important for the drying chamber (static or conveyorised) to have good air circulation with air supply and extraction facilities. Convection dry Recommended drying settings and hold times will vary with hardener selection, see below. Hardener Recommended/Max temperature Recommended/Max time (mins) Max hold-time after optimum tack-dry H /80 C (167/176 F) 40/60 72 hours IR Drying IR drying is dependent on coating application method, IR wave-length and IR intensity. Please contact Electra Technical Support Department for recommendations regarding specific equipment types and manufacturers. Page 5 of 10

6 Exposure Spectral output: Step wedge: nm. Optimum wavelength is approx nm clear (Stouffer 21 step). Note: exact millijoule requirements will vary with formulation type. Determination of the correct exposure should be carried out after setting the developing speed since this will affect the step wedge reading obtained. Step wedge checks should be carried out on brushed copper with the step wedge under the phototool. Energy level should be measured through the artwork and mylar/glass. It is important to recognise that the energy level should only be used as a guide for setting the correct exposure; step wedges should be used for determining the actual exposure setting. Separate exposure tests should be carried out for each different colour, as variations in lamp emissions can cause differences in exposure speed. After determining the correct setting, energy level can be monitored as a means to check for any changes in lamp output. Developing Developer: Spray pressure: Spray time: Temperature: 1% soln sodium or potassium carbonate kgcm -2, psi, Bar 30-90s in carbonate chamber(s) (dependent on quantity of ink in holes). 35 to 40 C ( F) Boards should be well rinsed with fresh water and fully dried after developing. Do not final cure boards when wet. The optimum developing speed is set when an unexposed board develops off completely, 25-50% of the way through the machine. This speed should be ascertained by preliminary tests prior to making exposure tests. Developing speed and break-point settings will be determined by the amount of ink deposited in the holes during coating. Due to the varying degree of ink deposited in holes, different application methods will require different developing speeds. Typical developing speeds using a 2m long carbonate chamber: Screen-print 1.3 to 2.0 mmin -1 Air-spray 3.0 to 4.0 mmin -1 Final Cure Convection oven: 60 mins at 150 C (300 F) Time at board temperature Page 6 of 10

7 UV bumping It is not normally necessary to UV cure Carapace EMP110 HD but under certain conditions it may be advantageous (see below). Under these conditions, conveyor speeds should be set to attain 1500 to 2000 mjcm -2. High film weight plating: When depositing high filmweights and/or coating heavily plated tracks it is sometimes possible to see slight wrinkling of the soldermask between the tracks after final cure. UV curing before final cure may prevent this. Flux residues/staining: Occasionally flux residues or staining can be seen on boards, particularly after Hot Air Solder Levelling with very acidic or aggressive fluxes. Washing boards when still hot causes this and can be exaggerated by using hot water rinse. Boards must be allowed to cool after soldering before rinsing and it is recommended all rinse solutions be below 40 C (104 F). If staining does occur it can be removed by post baking boards, after soldering, for C ( F). Alternatively if it is not possible to cool boards after HASL, staining can be prevented by giving boards a UV bump cure after the final thermal cure. Reduced ionic contamination: Certain fluxes, in conjunction with a poor recirculated-rinse after HASL, can lead to increased levels of ionic contamination. Although Carapace EMP110 HD has proven to give very low contamination figures, in these extreme cases a UV bump after final cure will reduce the risk of increased levels. Reduced soldermask outgassing: Where important soldermask outgassing can be reduced by a post-cure UV bump (see page 9). Via hole plugging Carapace EMP110 HD can be used for reliable via-hole plugging during the initial soldermask print stage. In order to achieve 100% of holes plugged it is advisable to use a double print stroke. In order to avoid splitting or blistering of the vias please note the following: Tack-dry: Exposure: Developing: Minimum of 40 mins at 80 C (176 F) Minimum clear 12 using Stouffer 21-step wedge Minimum speed to ensure required holes wash clean If the board design requires prolonged developing times due to small hole development it is recommended boards are given a pre-bake after developing before final cure to allow slow release of any trapped moisture from vias. Although it is not recommended to UV bump before final cure, it is advisable to pre-bake boards prior to passing through the UV curer if utilising a UV bump at this stage. Pre-bake: 15 to 30 mins at 70 to 80 C ( F) Page 7 of 10

8 Safelight It is not normally necessary to print Carapace EMP110 HD under safelight conditions, although it may be advisable if there are long delays before drying. Between drying/exposing and exposing/developing, boards should be kept in yellow light. Boards should, in any case, be kept out of direct sunlight until completely processed. Notation / Legend / marking inks Both UV and thermal curing notation inks are suitable for use with Carapace EMP110 HD. Thermal curing inks may be applied before or after final cure. If UV curing notation inks are used they should be applied before final cure and before UV bump if this is used. In this case UV curing the notation ink will serve as the bump for the soldermask. If using EMP110 (or ELP112) for LPI legend then the use of pre-pigmented matt finish paste formulations (or transparent + EP pigment concentrates) is recommended. A partial cure (30 (300 F) is recommended prior to LPI legend application. H-4090 colours are not suitable for legend applications. Stripping After developing, any reject boards may be stripped of soldermask using a 5% NaOH solution at C ( F) After curing, soldermask can be stripped using a proprietary soldermask stripper such as ES108H/4000 Cleaning Equipment should be cleaned of residual soldermask using SW200 or Dowanol PMA. Shelf-life Store at C (50-77 F), away from sources of heat and direct sunlight. EMP110 HD pastes have a minimum 12 months from date of manufacture All H-4090 products have a minimum of 24 months from date of manufacture Page 8 of 10

9 Final Properties TEST METHOD RESULT CLASSIFICATION Hardness (pencil) 6H Adhesion (Rigid) Copper: 0% removal Base laminate: 0% removal Chemical resistance Isopropanol (min.120s) Isopropanol/H 20 (75/25) D-Limonene 10% Alkaline detergent Monoethanolamine Deionised water Room temp. 120s 46 (± 2) C 15 min Room temp. 120s 57 (± 2) C 120s 57 (± 2) C 120s 60 (± 2) C 5 min No surface roughness No blisters No delamination No swelling No colour change No cracking Methylene chloride Internal testing:- Room temp. 60s Pass Hydrolytic stability No evidence of reversion Insulation resistance Before solder After SnPB After SAC E+12 Ω (avg.) 3.5E+-11 Ω (avg.) 3.3E+12 Ω (avg.) min req. 500MΩ (5.0E+08Ω) Moisture & insulation No blistering, separation, degradation. Initial (Ω) (avg.) During (Ω) (avg.) After (Ω) (avg.) No solder 1.1E E E+11 SnPB 3.5E E E+11 min req. 500MΩ (5.0E+08Ω) Resistance to Lead- Free Solder Simulation of Lead-Free Reflow SAC E E E+11 No adherence of solder to the soldermask surface No adherence of solder to the soldermask surface Adhesion to other soldermask materials 0% removal Wave-solder resistance 10 (± 1)s at 260 (± 5) C No loss of adhesion or solder pick-up. Hot-air-solder-level N/A Minimum 5 cycles Pass Thermal shock SM840 E No cracks, delamination, crazing or blistering Pass, class H Page 9 of 10

10 TEST METHOD RESULT CLASSIFICATION Dielectric strength SM840 E IEC and IEC KV/mm (3417 V / mil) Pass, class H Dielectric constant 4 (1 MHz) Soldermask Outgassing Total Mass Loss (TML) Collected Volatile Condensable Material (CVCM) Water Vapour Recovered (WVR) ASTM-E-595 requirement Max. 1.0% Max. 0.10% Report EMP110 No UV bump 2.58% 0.06% 0.31% EMP110 Plus 3200mJcm -2 UV bump 0.95% 0.02% 0.31% Other Bellcore TR-NWT Pass IPC-SM840E Class H BS6096/9000 Pass MIL 55110D Pass Siemens E-korrosion Pass The Laboratories at Electra Polymers Ltd. have taken all reasonable steps to ensure that the information set out above is accurate within the scope and limitations of our existing knowledge and experience. Since, however, we cannot anticipate or control the many interrelated conditions under which our products are used, all our products are offered for sale and trial on the basis that clients will satisfy themselves by tests or otherwise on these products, that they are fit, suitable and safe for the purpose for which they are required, within the parameters and conditions in which they will be used. In cases where our products are found to be defective in material and workmanship, our liability is limited to the purchase price of the products found to be defective. THIS WARRANTY IS TO THE EXCLUSION OF ALL OTHER WARRANTIES OR GUARANTEES, EXPRESS OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE, DESCRIPTION PRODUCTIVENESS OR ANY OTHER MATTER. None of the above information may be construed as a recommendation that our products be used in violation of any patent rights. We accept your orders at our shipping points only on the basis of the above understanding, set out in our detailed "Standard Terms + Conditions of sale". E & OE. For further information, contact: Electra Roughway Mill Dunk s Green Tonbridge Kent TN11 9SG ENGLANDTel: +44 (0) Or visit our Website for details of local offices and Distributors Page 10 of 10